After reading the thread on feathered landings and discussing multi-engine training with some of my colleagues. The general opinion is that asymmetric training is more realistic when engine failure is simulated by cutting the mixture even though there is a certain amount of risk attached. Yet looking at the CAO’s, the requirements for a light twin to continue climbing away all be it at 1% climb gradient is only required AFTER the prop is feathered and gear and flap retracted. However It’s discussed quite openly EFATO is practiced just as the aircraft lifts off with both the gear and flap still extended and the method of simulating failure is by cutting the mixture.
There was an article in the Safety Digest published by CASA on multi-engine training that the preferred method of simulation was by closure of the throttle and setting zero thrust to simulate a feathered propeller. Yet the old method of EFATO simulation using the mixture control is still practiced even though it has caused several accidents. To add to this why does this exercise have to be conducted just after lift off when the gear and flap are still extended and the risks greatest. Even the performance requirements do not call for the aircraft to perform in that configuration. Perhaps a CASA Flight Ops Inspector would like to comment on this type of training.
It's a long time since I have been involved, so memory is a little hazy.
Conventional wisdom in the past was that a mixture cut was easier on the engine as the loading stays positive. If the throttle is pulled abruptly backloading occurs, which can do nasty things to dynamic balances. Additionally if the engine is of the geared variety the lay shafts take a caning.
The procedure called for the establishment of zero thrust when the candidate had correctly identified and simulated feathering. This would be done after the candidate has "confirmed" with throttle, and left the throttle on the back stop. Thus when the mixture is returned to full rich the loads are all the right way around.
Tell me how would you simulate confirmation after a throttle cut simulation? Perhaps you feel it is uneccessary to confirm. Short cut to an incorrect shutdown methinks.
Why is it done just as the aircraft breaks ground? Cos that's the most critical phase, and what needs to be experienced and practiced. If you have a failure at that point and don't do it correctly the ground WILL come up and smite thee, so why not practice it at training weights and with a professional at your side.
It is because of the criticality of the procedure that ME Training approval used to be hard to achieve. A situation that is no longer the case, if I understand the current state of play correctly.
This refers to initial piston twin endorsement only. Turbo props an entirely different matter, but by then the guy in the left seat should know the basics. Jets another kettle of fish and a whole lot easier still.
I see your point on engine loads, however why would CASA suggest closing the throttle in the Safety Digest if it didn't adequately simulate an engine failure and the drills that followed, surely there has to be some merit in their suggestion.
firstly, the safety digest is full of one eyed opinions from others in industry looking to have their moment in the sun. It is a very long bow to suggest that becasues a particular point of view is presented, it represents all CASA FOI's. The only concensus here would be they all don't agree.
Second, most training providers that do M/E training that I have worked for use the mixture as it is kinder to the engines (loading as already stated). This becomes even more important when you introduce turbos and geared engines.
so why not practice it at training weights and with a professional at your side.
I seem to recall the fatal Duchess accident at Camden a couple of years back that caused the death of the instructor and terrible burns to the student. The student had a "professional" at his side, too... And oh yes - it was a simulated engine failure caused by a mixture cut.
Re mixture cuts. I seem to recall the fatal Duchess accident at Camden a couple of years back that caused the death of the instructor and terrible burns to the student. The student had a "professional" at his side, too... And oh yes - it was a simulated engine failure caused by a mixture cut.
That was horrific, some 40,000 hours between them too, what a shocking waste.
Confirmation of an engine failure and identifying the correct engine is simple. For arguments sake if one was just sitting with their hands and feet off the controls the yaw itself would tell you which engine has failed. Yaw left left engine failed, yaw right right engine failed. Now assuming you have your hands and feet appropriately placed you can use the dead foot dead engine to further confirm which engine has failed. So confirmation is not a problem, in addition just because one pulls back the correct throttle lever, who is to say that you will not pull the wrong pitch or mixture control.
So the next point which I fear is more relevant, are we failing or simulating engine failure with mixture to reduce wear and tear to reduce costs thereby putting maintenance costs ahead of safety?
I was trained using the mixtures cut 30 years ago but then I was young and didn’t know better, fortunately now this is all done in a simulator. I am all for realism but not when safety is an issue. Perhaps if Multi Engine Training incorporated more use of the simulator where procedures could be honed it would be best for all. One thing I did notice at some of the flying schools was the availability of twin simulators which were not around in my GA days.
The Lycoming Flyer Key Reprints 1992 on page 49 has this brief (slightly edited for brevity) warning by the US NTSB. "The fatal crash of a light twin in which a flight instructor was killed prompted the NTSB to issue an urgent warning to all pilots simulating an engine-out condition on multi-engine airplanes. The Board's investigation revealed that some flight instructors do use the mixture control or fuel selector to shut down an engine to test a multi-engine applicant. Although this is a recommended procedure, the urgent warning was aimed at flight instructors who were using this procedure at altitudes too low for continued safe flight. The NTSB observed that use of such procedures at traffic pattern altitudes may not permit instructors enough time to overcome possible errors on the part of the applicant. The recommendation by the NTSB means all simulated engine-out operation at lower altitudes should be accomplished by retarding the throttle and this should be done slowly and carefully to avoid engine damage or failure."
One presumes the term "lower altitudes" used by the NTSB covers simulated failures after lift off and below circuit height?
I think a point that constantly gets missed on this topic is, what caused the accident? Did the aircraft concerned at Camden crash because the mixture was cut? Or was it because the aeroplane was too low, or got below Vmca? Would the accident still have happened if the throttle was used in leiu of the mixture?
It's fine to say 'mixture cuts are bad' but is that the real reason of the accident?
I think more of concern is what happens AFTER the failure has been simulated, ie airspeed, height terrain clearence ahead etc etc.
The point being missed is that mishandling on each occasion has caused accidents. By using the mixture one does not have the option of restoring power to the other engine quickly, so why take the risk when you have other options.
One plans an alternate when the weather is bad, to have an option. However with a mixture cut followed by mishandling just after take-off the option is the coffin.
I wonder why airlines use simulators for this sort of exercise. It’s a pity CASA does not put an end to this stupidity
How many seconds is it from Mixture cut-off back to full rich? How long does it take before the engine kicks back in? Serious question I don’t have META so have never had the opportunity to try it myself. In most cases the throttle is back to idle before the mixture goes rich, so what happens if you leave the throttle open?
In my experience of giving multi engine training using mixture cuts the engine starts immediately when the mixture is returned to rich...unless you have feathered the prop etc...which you generally don't do.
While the mixture was used to give the initial 'failure' as soon as the student had correctly identified the failure and carried out the memory items I would reinstate the mixture and set zero thrust on the now running engine.
The MOST important point of all is where you fail the engine not how. Any really experienced multi piston pilot uses 'gear up' as their decision point...i.e. if the engine fails before gear up I close both throttles and land straight ahead irrespective..after gear up it is memory items and fly if possible (and most DO despite the rhetoric). Of course it is a little situation specific and a decision will (should) have been made before commencing the takeoff based on knowledge of the aeroplane and the ambient conditions. A light twin at MTOW on a 40deg day will not fly on one so you would be predisposed to a controlled forced landing before even setting takeoff power.
That many multi instructors feel the need to fail engines right on lift off with the gear still down indicates ignorance and inexperience.
On the odd occasion when I have needed to climb into a piston twin with an unknown individual in the RHS I have made it ABUNDANTLY clear that if they fail an engine on me below 200' with the gear down I WILL land straight ahead with NO compunction whatsoever...If I bend metal it's their problem. Whether it was my tone of voice or the look in my eyes I am not sure but none have ever tried it on.
Morons have caused piston twins to have the reputation they have not the aircraft themselves. ANY piston twin flown correctly is 'safer' than a single. But that is the rub...since most piston twins passed from the hands of 3rd level airlines to small charter companies 15-20 years ago there has been a HUGE loss of corporate knowledge on how they should be flown.
The average CASA FOI is part of the problem not the solution.
Sorry guys for being so inprompt but lets put the the ballsand ego toone side for a second and think about this. One thing which much be remembered is that we a simulating a failure and as a M/E instructorshould never cause an intentional failure. If your argument is so that they close the throttle WHO CARES???? REALLY? Is is so critical that they will remember on the once off? just look a sim check rides... how many pull the wrong fire handle under the pump? Secondly, If you willing to risk your life that the student will handle the situation correctly... well good luck and I wish you all the best, but will you put you Life, friends and family behind that one? Thirdly, As for reducing engine ware and tare..... I think its a whole load of brown stuff. You run an engine at 350 degrees and make it feel 22 degree air in the space of a few seconds..... now lets see who has the real failure (forgetting a geared engine). Just some common safety tips fellas.. what you do is your own life
It would be great if there was a full motion simulator for a Duchess/Seminole/Seneca etc but there just isn't.
In my few years doing ME Tng, I never ( and I think it was ops manual) failed engines below 300ft after take-off. I personally used the mixture control based on recomendations from Lycoming and info from the key reprints articles. Someone asked how quick? Immediately. Possibly even quicker that opening the throttle. How many touch and goes have started with cough-cough-cough stutter and then power.
In demonstrating the pitfalls of low level failures, think about how we demonstrate stalls. Why not set the aircraft up in t-o config climbing at the appropriate speed for type and then passing the pretend ground at 2000-3000ft agl, fail the engine. It might lack the bravado and adrenalin rush that some might love, but it works as a safe demonstration as to the performance or lack thereoff of light twims.
Lessons have to be learnt but think a little laterally and you'll be able to find safe ways to teach most areas. Think closely about the other things we do as instructors, single engine EFATO/solo PFL practice/ SE NVFR, is a PROPERLY managed exercise all that dangerous. Don't try this stuff at night as some have attempted.
I never ( and I think it was ops manual) failed engines below 300ft after take-off. I personally used the mixture control based on recomendations from Lycoming and info from the key reprints articles
Well done. Now lets examine carefully exactly what Lycoming said in their magazine Key reprints as to the why's and wherefores of throttle versus mixture. Page 50 states among other things: "Many flight instructors down through the years used the technique of abruptly cutting an engine with a multiengine candidate to test his emotional reaction (??is the instructor a qualified psychologist - I think not) and judgement with this extreme technique. Big radial piston engines with short stubby crankshafts could tolerate this abrupt (throttle) technique. However, flat opposed piston engines with their long crankshafts and attached counterweights could not as readily take the abuse of suddenly snapping a throttle shut, particularly at take off or climb power. Use of the latter technique would tend to detune crankshaft counterweights and could possibly result in a nasty engine failure.
Since it was common technique by flight instructors to terminate power abruptly to simulate engine power loss, we had to protect the engine. As a result we published in our Engine Operators Manual and in Service Bulletin No. 245, the recommendation that if the power was abruptly terminated it must be accomplished with the mixture control. Of course, this was intended for higher altitude where a complete engine shut down could be conducted safely. However, any practice of simulated engine-out condition at low altitude should be best accomplished by a slow retardation of the throttle in accordance with the NTSB recommendation."
So this suggests that the abrupt ripping back of a throttle was likely to cause engine problems. A slow throttle closure will not cause engine problems and has the added advantage of instant power available if mishandling occurs by either pilot. The mixture cuts were there to stop ham fisted instructors from stuffing the engines by abrupt throttle handling. That was the reason that Lycoming said mixture cuts were better for the engine. As Lycoming said - "We had to protect the engines" (from ham fisted instructors) And as for instructors testing the emotional reaction of candidates - surely that is a job for professional psychologists - not enthusiastic amateurs?
Centaurus, I understand your passion of using throttle to simulate failures instead of the mixture, but can you perhaps answer what I asked in the post above? Has cutting the mixture directly caused an accident? As Chimbu said, usually once the student has called for feather, zero thrust was set, so I fail to see how cutting a mixture = accident. Perhaps handling AFTER the failure is the more prudent point. When I DID conduct engine failures using mixture cuts, I had my own personal limits ie not <300' no rising terrain ahead (ie north rwy at Cobden etc) prior to doing that. However, this thought process didn't stop when I started using throttle cuts!! Point is, what difference does it make? I am not trying to suggest that cutting mixtures willy nilly is a smart move, but nor is the throttle for an 'unsuspecting' student.
I also would like to see any data or evidence that advancing a throttle to full, versus a mixture to full is going to apply power any sooner.
Granting of training approval and a delegation, transfers a reasonable amount of discretion. Provided the training covers the requirements and is conducted within broad parameters, all is well.
We all determine what is acceptable to us. If you determine that you require a lesser standard of demonstrated ability, than does a brother instructor/delegate, then that is a matter for your conscience.
I trust it will not come back to haunt you. I hope you never have that nagging feeling “could I have better prepared Blogs to look after the passengers he has just killed.”
Training is an inherently risky business. While I would never suggest that one should not try to reduce risk, there must be a point of balance. Obviously you have determined the balance you find acceptable. It is not mine.
No one here has suggested that we do multiple failures at critical points, however is it not reasonable to finish off with a couple at awkward times, to verify the integrity of the training and assessment.
You seem to have access to good resources. It would be interesting to research how many passengers have died from VMCA/stall/spin asymmetric accidents, as opposed to the number of instructors and Blogs lost in training. (Military excluded)
MBA747
You are confusing “identification” with “confirmation”
When using the mixture, you do have the ability to restore, and within a poofteenth of a second of the time it would take with throttle.
Chimbu Chuck
If you tried that sort of standover tactic with me I would be inclined to walk away and let you find someone else to do the test. That is not to say that I would do anything that might upset you, but you would have already demonstrated an attitude and inflexible mindset which in my assessment would disqualify you from the privileges of the rating. Fortunately for both of us I am no longer involved in that area.
Maui, that's not a standover tactic, that is a take-off briefing. "In the event of an engine failure below 200', with the gear down, I will land ahead regardless of whether It is simulated or not."
Linear Mode
